Kubernetes on IPv6 only

Kubernetes is an open source platform for managing containerised applications.

IPv6 is the next generation Internet protocol, and running on IPv6 only simplifies configuration and administration, and avoids the performance issues and complexities of IPv4 encapsulation, NAT, and conflicting private address ranges.

The default configuration of Kubernetes is IPv4, and there are few, and scattered, examples and guidance for setting up IPv6 dual stack, let alone single stack.

I have collected instructions from the different sources into a single guide to successfully deploy Kubernetes with IPv6 only.

See the guide for full instructions:


The blog post contains some additional background on what I did to gett the deployment working. The deployment was tested on Ubuntu 20.04 running on an IPv6 only virtual server from Mythic Beasts.

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IPv6 only hosting

We ran out of IPv4 addresses a few years ago, and the cost has been steadily increasing, now over USD 25.00 per IPv4 address.

Meanwhile we are increasingly using technologies such as containerised deployments and mass deployment of Internet of Things (IoT) devices, seeing an increase in demand for addresses.

About 30% of the Internet now happily talks IPv6, with several countries having more than 50% IPv6, and for a server hosting environment there are many benefits to going IPv6 only.

IPv6 only hosting is available from several providers such as Mythic Beasts.

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Surviving with IPv6 only

Trying to use an IPv6 only machine runs into a roadblock when you need to access a legacy IPv4 resource.

The best solution would be to convince services to move to an IPv6 first solution, incrementally adding reverse proxies for existing services and deploying new services to IPv6 only, with an IPv4 gateway only as needed.

Deploying new services to IPv6 only is much simpler than dual-stack, as you only need to worry about one set of configuration, firewalls, etc. Adding an IPv4 proxy on top, for legacy support, is then a simple, and contained, extension.

However, until that happens you still need a solution.

I found setting up DNS64 + NAT64 for my IPv6 only machines was pretty simple with my OpenWRT router.

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Ubuntu, Raspberry Pi, IPv6 only

There are very simple instructions for installing Ubuntu on a Raspberry Pi, simply downloading the Imager and then pick the OS (which it will download for you, I used Ubuntu Server 20.04 LTS), and write it to the micro SD card for your Pi. https://ubuntu.com/tutorials/how-to-install-ubuntu-on-your-raspberry-pi

The image is pre-configured for DHCPv4 using the wired Ethernet connection, with alternative instructions for getting it setup with Wi-Fi, but without mention of IPv6, which is now used by 30-35% of the Internet.

Here are instructions for setting up Ubuntu on your Raspberry Pi up with IPv6 only.

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Open Source Compatible Fonts

One page reference chart of open source fonts that are size-compatible with well known standard commercial fonts.

There are, of course, a large variety of style open source fonts as well, for all manner of uses. But for basic documents, consider using Nimbus Sans or TeX Gyre Termes instead of your system default.

This blog is (currently, November 2020) in Noto Serif, from the worthy Noto project trying to cover the entirety of Unicode.

A Guide to W3C Trace Context

Earlier this year the W3C Trace Context Recommendation was finally published. A standard way of passing distributed trace correlation has been needed for a long time, and it is good to see there is finally a standard, and many vendors have already moved to adopt it.

The Recommendation defines what a distributed trace is:

A distributed trace is a set of events, triggered as a result of a single logical operation, consolidated across various components of an application. A distributed trace contains events that cross process, network and security boundaries. A distributed trace may be initiated when someone presses a button to start an action on a website – in this example, the trace will represent calls made between the downstream services that handled the chain of requests initiated by this button being pressed.

What constitutes a single logical operation depends on the system. In the example above it is a single button press on a website, whereas in a batch processing system it might be for each item processed, or in a complex UI it might consist of both a button press and a subsequent confirmation dialog.

The W3C Trace Context Recommendation describes how the correlation information — an identifier for the operation, and the parent-child relationships between components — is passed in service calls, but doesn’t cover what to do with that information, apart from how to pass it to the next component.

This is a guide mostly how to use Trace Context for logging, although it also applies to metrics and other telemetry.

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3d6 is not less swingy than d20

With tabletop roleplaying game (RPG) systems, sometimes I hear a claim that bell curve dice rolls, e.g. 3d6, are “less swingy” (less variance) than a linear based dice roll such as d20 or d%.

This is, however, incorrect.

While the distribution of dice rolls are different, the distribution of outcomes – success or failure – are the same, and for equivalent circumstances have the same statistical variance / standard deviation.

Although the outcomes have equivalent distributions, the underlying type of dice system is important for analysis of modifiers and skill progression.

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Estimation worksheet

This is a worksheet I have had for a while for calculating estimates using not a single value, but three values for best case, most likely case, and worse case. The values are combined using the PERT formula, to calculate a total estimate, statistical ranges, and an overall estimate including contingency.

Download the worksheet here:

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Supply Chain on Blockchain – conference review

On Monday, I attended the Supply Chain on Blockchain conference (https://scobc.net/), usually held in Brisbane, but this year run online.

Here are my impressions of the different sessions I attended. My highlight of the conference was the second keynote from John Wolpert, on the Baseline Protocol project.

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